Rotary compressor.



W. KIESER. 4

ROTARY COMPRESSOR.

APPLICATION FILED mme, 1911;

1,056,689, Patented Mar. 18,1918.

Ihventor, Walter Kieser;

Witneses:

wALTER'iEsER, oF

CHARLOTTENBURG, GERMNY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ROTARY COMPRESSOR.

Specication ofLetters Patent.v

Patented Mar. 18, 19,13.

Application filed .Tune 6, 1911. Serial No. 631,592.

To all whom t may concern.'

Be it known that I, WALTER KIESER, al

citizen o-f Switzerland, residing at Charlottenburg, Germany, have invented certain new and useful' Improvements in Rotary Compressors, of which the following is a specification.

-The present invention relates to rotary compressors for compressing elastic fluids such as air, etc., and has for its object to improve their construction whereby their etliciency will be improved by overcoming certain faults that are now present.

My invention has particular reference to the construction of the annular fluid discharging and directing device that surrounds the impeller and which receives the fluid therefrom and converts its velocity into pressure. As heretofore constructed -the fluid passes in this directing device has they are the cause of certain losses for the following reasons: First, because the medium leaving the impeller does not enter the directing device in close jets on account of #che blades of the impeller having substantial thickness at their outer ends where the Huid escapes, this being necessary to withstand the .centrifugal and mechanical stresses, and second because the annular discharging device must have the same width as the impeller to avoid impact of the fluid. in passing from one to the other. If the streams of fluid -leaving the impeller have spaces between them, it follows that 'on entering the discharging device the fluid will suddenly expand. Further, in the wide directing passages or channels heretofore used and which extend radially outward, the velocity of the fluid is ra idly transformed into pressure by reason o the large internal section of the passages. Another prejudicialaction is due to the fact that the vane spaces in the impeller are never completely filled with the fluid undergoing compression so that the fluid on leaving said impeller and entering the directing device will suddenly expand in the fluid passages of the latter. To avoid all of these disadvantages, I provide the Huid dischargingand directing device With a receiving portion that. is sufficiently large to properly receive the fluid and whose cross section is gradually contracted'outwardly/from the point of admission to what maybe termed the'throat. The contraction of the passage or opening in the receiving portion may be obtained either by the mutual axial approximation of the walls of the receiving device -or by introducing one or more suitably formed partitions, walls, or vanes in the channels or passages contained in saidreceiving port-ion. This arrangement prevents a sudden fall in pressure of the fluid undergoing compression prior to the actual transformation of velocity into pressure in said device.- The contracted portion not only serves to conduct the fluid at its greatest density as received from the impeller to the directing device proper but also renders it possible `to supply fluid to said device without danger-of impact losses whereby the transformation of velocity intoI pressurein said device may take place quite gradually, the latter having fluid passages whose cross section gradually enlarges as the distance from the axis of the impeller increases. This gradual transformation of velocity into pressure is of prime importance.

In the accompanying drawing, which is illustrative cfm-y invention, Figure 1 is an axial section of a part of a compressor; Fig. 2 is an axial section of a part of a mlltistage compressor showing partitions, wa s or vanes in the passages in lthe receiving anddirecting device; and Fig. 3 is a detail view showing the arrangement heretofore used and which is open to the disadvantages enumerated above.

1 indicates the shaft and mounted thereon is an impeller 2 having Vanes 3 between which are outwardly' opening passages 4. The periphery of the impeller 1s turned true and 1s inclosed by the fluid receiving,direct 4is supportedby the .Walll't-hatmayfforin a* ing and 'discharging 'd f .vice.5.L n .device part of a diaphijagrn, the casingorother verge-to tghe throatQSl 'At this point the 1 -passages 9 in t-he"directingl device proper begin. .The-passages are formed byu side Walls `l and/1l and iiartitio'ns 12. vThe' cross-sectional Jarea of said passages graditi-1. allyy increases as 'fthe distance; from the vshaft increases.- 1- The vpartitions 12 maybe of uniany eventyity lwill be noted that the 4space between the pitch centei'fsf off'the partitions will; be greater, measured 1circuinerentially,y y at `the'outer than the-inner diameter. This y arrangement providesv afsiinplle andy IeasyA Way for obtaining the proper increased area .Ofi-he passagesf. l `I lIn Fig. 2 an arrangement is shown for lconveying fi'uid from the discharge side. off fone .impeller to the inlet of anothermounted on the same shaft.` TheA directing device is i. provided/with a receiving portion 7 and a fluid conveying passage 9 connected thereto.

, Isaid portion and passage is located a. partiti0n13 that is sharpened atfthe end' adjacent the impeller and as" the Wall thickens to' vthe point. of niaxiinninrsection a `two-part! throatlsA yis formed, and from said throat to vthe point'of discharge the velocity of the Huid is .gradually converted into pressure.

When the partitions Vare used-iii a multiy.stage,compressor as shown ini-Fig. 2, they ,neednot extend inwardly but may stopl f `short of a complete turn as shown', since I the section of the passage will gradually de- 1.40` l should be. taken to see that the outer end of crease as they approach the shaft. .'Care each partition is tapered to avoid sudden changes in Isection of the fluidpassages.

The passages 15 an'dlG on opposite sides of the ypartition gradually enlarge beyond the throat to convert the velocity of ythe fluid into pressure.

The method of operation vis as follows:

The fluid on leaving the vane spaces in theiinpeller. is received by the receiver' or rereiving portion of the directing device 5 A:i5 place. The pressurev of the fluid leaving the and is prevented from expanding bythe contracting Walls thereof. It'is then sup? plied to the directing device proper wherein the conversion of velocity into pressure takes inpeller andth'atv entering the passages 9 shouldbe the same. The height of the constriction is the same as that of the passages in the-device .communicating .therewi'tnso lthat there Will be' a 'gradual transformation 'of the velocity of theliiid .into pressure. By means of the structure illustrated, sud- `den impacts of the fluid are avoided in passing from the inipeller tol the directing de-` `other hand, if the partitions in the other means.

vice and.'a'l'so 4the too rapid. transtornialion of thef`velocity`oi the liuid into i'ircssure Whichwould cause corresponding losses.

Viewed from one point the Walls that forni the constrictedchamber, passage or passages 'il"donotgforin'aipart of the fluid directing .and discharging device proper and may for 'thatlreasonbe made ofseparated but united' parts."From-another point of view, the

`fluid directing vand Idischaiging device may beftlaken to` include the whole structure that l y acts onli-hc `fluid afteiit. -leaves the impcllcri A i form section throughout -theirdengt'h ortheyV Y may Ihevaried as circumstances dictate. In '15 In Fig.' 3 is illustrated the ordinary conl`stri'uc-tion ein'ployed before iny invention which vis open' to the objectioi'is prcviouSly noted.A It will be observed that the beveled ends 'of`v the vaiicsfl? on .the inipellefr and ofthe partitions 1S in the directingdevice are Arelatively thick which results vin a pluralityI of individual separated fluid streams which, unless thel passages 1n' both `members register, ivill'strike on the ends of the partitions. It will further he 'seen that. the linlet areav of" the directing spaces greater than" the outlet area of the iinpellcr spaces and hence there will be an objectionable and sudden change in pressure. In this connection it shouldbe' observed that the mouth. of veach passage in thel directing de-y .'vice Inustbe at least as long, measured, aikially, as the outlet of each vane passage in the inipellersince otherwise the fluid undergoing compression' will escape. "On the device are thickened to reduce the cross section the trouble incident to the Huid streams directing striking their ends Willbemgreatly increased.

'with the apparatuswhich I- now consider to represent the best Vembodiment thereof; y

but I desire to have it nnderstoodthat the apparatus shown is only. illustrativeyand .that the invention can be carried out by What-I claim as netvand desire to secure by Letters Iatent of the'United- States, is,

1. In a rotarvcompressor, the combination of an impeller' that imparts velocity to the Huid, Wi-th. adirccting device which receives the 'fluid undergoing compression from the impeller forI converting velocity into" pressure, said device being provided with a portion containing one or more passages that decreasein cross section vas the 'dist-ance from the iinpeller increases for the `purpose of collecting the fluid, preventing expansion thereof and delivering it to the directing device at-the`v density it had when leaving the impeller. i

2. In a rotary compressor, the eombination of an impeller that imparts velocity to` I the fiuid With a fiuid directing device which comprises an inlet portion having convergdischarging portion receivin thelpassage, said portion having walls'andj,"

ing walls forming a passage whose crosssectional area `decreases as it extends in the direction of flow to prevent change in the density of the'uid leavin the mpeller and to collect it, and a iui directin Hand Huid from,

and prevent it from expanding or chang- 'ing its density, and a` discharging portion having passages which receive fluid' from the collectlng passages andl convert its velocity into pressure, and partitions in the Vthe passages ofhoth Aof said portions which are tzlilpered at their receiving ends toform a t roat.,:` v

f 4.111 ,al rotary v compressor, the combination of an'impe'l1er,`w1th a uid dischar ing ing passages wi converging outwardly toward the throat and reveting a change in the density of uid leavingV the limpeller as it passes to said throat and the other divergingoutwardly from the throat.

.In witness whereof, I

my hand. i

" WALTER KIESER. Witnesses: i"

Basins/ARDv RrmNow, HERMANN HILLE.

@epics of this patent may be obtained for veA cents each, by addressing the Commissioner of Patents, i

Washington, D. C,

have hereuntoset `device which surrounds the impeller an rec eivesl theuid therefrom," the said device comprising two principal portions each havt a throathetween each two;` registering passages, one setof 'passages 

